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SELinux: Add a network node caching mechanism similar to the sel_netif_*() functions 

This patch adds a SELinux IP address/node SID caching mechanism similar to the
sel_netif_*() functions.  The node SID queries in the SELinux hooks files are
also modified to take advantage of this new functionality.  In addition, remove
the address length information from the sk_buff parsing routines as it is
redundant since we already have the address family.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Paul Moore 2008-01-29 08:38:13 -05:00 committed by James Morris
parent da5645a28a
commit 224dfbd81e
5 changed files with 416 additions and 17 deletions
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9
security/selinux/Makefile
View File

@ -4,7 +4,14 @@
obj-$(CONFIG_SECURITY_SELINUX) := selinux.o ss/
selinux-y := avc.o hooks.o selinuxfs.o netlink.o nlmsgtab.o netif.o exports.o
selinux-y := avc.o \
hooks.o \
selinuxfs.o \
netlink.o \
nlmsgtab.o \
netif.o \
netnode.o \
exports.o
selinux-$(CONFIG_SECURITY_NETWORK_XFRM) += xfrm.o

33
security/selinux/hooks.c
View File

@ -76,6 +76,7 @@
#include "avc.h"
#include "objsec.h"
#include "netif.h"
#include "netnode.h"
#include "xfrm.h"
#include "netlabel.h"
@ -3395,7 +3396,7 @@ out:
#endif /* IPV6 */
static int selinux_parse_skb(struct sk_buff *skb, struct avc_audit_data *ad,
char **addrp, int *len, int src, u8 *proto)
char **addrp, int src, u8 *proto)
{
int ret = 0;
@ -3404,7 +3405,6 @@ static int selinux_parse_skb(struct sk_buff *skb, struct avc_audit_data *ad,
ret = selinux_parse_skb_ipv4(skb, ad, proto);
if (ret || !addrp)
break;
*len = 4;
*addrp = (char *)(src ? &ad->u.net.v4info.saddr :
&ad->u.net.v4info.daddr);
break;
@ -3414,7 +3414,6 @@ static int selinux_parse_skb(struct sk_buff *skb, struct avc_audit_data *ad,
ret = selinux_parse_skb_ipv6(skb, ad, proto);
if (ret || !addrp)
break;
*len = 16;
*addrp = (char *)(src ? &ad->u.net.v6info.saddr :
&ad->u.net.v6info.daddr);
break;
@ -3614,7 +3613,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
break;
}
err = security_node_sid(family, addrp, addrlen, &sid);
err = sel_netnode_sid(addrp, family, &sid);
if (err)
goto out;
@ -3826,7 +3825,8 @@ static int selinux_socket_unix_may_send(struct socket *sock,
}
static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
struct avc_audit_data *ad, u16 family, char *addrp, int len)
struct avc_audit_data *ad,
u16 family, char *addrp)
{
int err = 0;
u32 netif_perm, node_perm, node_sid, if_sid, recv_perm = 0;
@ -3886,7 +3886,7 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
if (err)
goto out;
err = security_node_sid(family, addrp, len, &node_sid);
err = sel_netnode_sid(addrp, family, &node_sid);
if (err)
goto out;
@ -3915,7 +3915,7 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
u16 family;
char *addrp;
int len, err = 0;
int err = 0;
struct avc_audit_data ad;
struct sk_security_struct *sksec = sk->sk_security;
@ -3931,13 +3931,12 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
ad.u.net.netif = skb->iif;
ad.u.net.family = family;
err = selinux_parse_skb(skb, &ad, &addrp, &len, 1, NULL);
err = selinux_parse_skb(skb, &ad, &addrp, 1, NULL);
if (err)
goto out;
if (selinux_compat_net)
err = selinux_sock_rcv_skb_compat(sk, skb, &ad, family,
addrp, len);
err = selinux_sock_rcv_skb_compat(sk, skb, &ad, family, addrp);
else
err = avc_has_perm(sksec->sid, skb->secmark, SECCLASS_PACKET,
PACKET__RECV, &ad);
@ -4158,9 +4157,11 @@ out:
#ifdef CONFIG_NETFILTER
static int selinux_ip_postroute_last_compat(struct sock *sk, struct net_device *dev,
static int selinux_ip_postroute_last_compat(struct sock *sk,
struct net_device *dev,
struct avc_audit_data *ad,
u16 family, char *addrp, int len)
u16 family,
char *addrp)
{
int err = 0;
u32 netif_perm, node_perm, node_sid, if_sid, send_perm = 0;
@ -4211,7 +4212,7 @@ static int selinux_ip_postroute_last_compat(struct sock *sk, struct net_device *
if (err)
goto out;
err = security_node_sid(family, addrp, len, &node_sid);
err = sel_netnode_sid(addrp, family, &node_sid);
if (err)
goto out;
@ -4245,7 +4246,7 @@ static unsigned int selinux_ip_postroute_last(unsigned int hooknum,
u16 family)
{
char *addrp;
int len, err = 0;
int err = 0;
struct sock *sk;
struct avc_audit_data ad;
struct net_device *dev = (struct net_device *)out;
@ -4262,13 +4263,13 @@ static unsigned int selinux_ip_postroute_last(unsigned int hooknum,
ad.u.net.netif = dev->ifindex;
ad.u.net.family = family;
err = selinux_parse_skb(skb, &ad, &addrp, &len, 0, &proto);
err = selinux_parse_skb(skb, &ad, &addrp, 0, &proto);
if (err)
goto out;
if (selinux_compat_net)
err = selinux_ip_postroute_last_compat(sk, dev, &ad,
family, addrp, len);
family, addrp);
else
err = avc_has_perm(sksec->sid, skb->secmark, SECCLASS_PACKET,
PACKET__SEND, &ad);

32
security/selinux/include/netnode.h Normal file
View File

@ -0,0 +1,32 @@
/*
* Network node table
*
* SELinux must keep a mapping of network nodes to labels/SIDs. This
* mapping is maintained as part of the normal policy but a fast cache is
* needed to reduce the lookup overhead since most of these queries happen on
* a per-packet basis.
*
* Author: Paul Moore <paul.moore@hp.com>
*
*/
/*
* (c) Copyright Hewlett-Packard Development Company, L.P., 2007
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#ifndef _SELINUX_NETNODE_H
#define _SELINUX_NETNODE_H
int sel_netnode_sid(void *addr, u16 family, u32 *sid);
#endif

9
security/selinux/include/objsec.h
View File

@ -100,6 +100,15 @@ struct netif_security_struct {
u32 sid; /* SID for this interface */
};
struct netnode_security_struct {
union {
__be32 ipv4; /* IPv4 node address */
struct in6_addr ipv6; /* IPv6 node address */
} addr;
u32 sid; /* SID for this node */
u16 family; /* address family */
};
struct sk_security_struct {
struct sock *sk; /* back pointer to sk object */
u32 sid; /* SID of this object */

350
security/selinux/netnode.c Normal file
View File

@ -0,0 +1,350 @@
/*
* Network node table
*
* SELinux must keep a mapping of network nodes to labels/SIDs. This
* mapping is maintained as part of the normal policy but a fast cache is
* needed to reduce the lookup overhead since most of these queries happen on
* a per-packet basis.
*
* Author: Paul Moore <paul.moore@hp.com>
*
* This code is heavily based on the "netif" concept originally developed by
* James Morris <jmorris@redhat.com>
* (see security/selinux/netif.c for more information)
*
*/
/*
* (c) Copyright Hewlett-Packard Development Company, L.P., 2007
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <asm/bug.h>
#include "objsec.h"
#define SEL_NETNODE_HASH_SIZE 256
#define SEL_NETNODE_HASH_BKT_LIMIT 16
struct sel_netnode {
struct netnode_security_struct nsec;
struct list_head list;
struct rcu_head rcu;
};
/* NOTE: we are using a combined hash table for both IPv4 and IPv6, the reason
* for this is that I suspect most users will not make heavy use of both
* address families at the same time so one table will usually end up wasted,
* if this becomes a problem we can always add a hash table for each address
* family later */
static LIST_HEAD(sel_netnode_list);
static DEFINE_SPINLOCK(sel_netnode_lock);
static struct list_head sel_netnode_hash[SEL_NETNODE_HASH_SIZE];
/**
* sel_netnode_free - Frees a node entry
* @p: the entry's RCU field
*
* Description:
* This function is designed to be used as a callback to the call_rcu()
* function so that memory allocated to a hash table node entry can be
* released safely.
*
*/
static void sel_netnode_free(struct rcu_head *p)
{
struct sel_netnode *node = container_of(p, struct sel_netnode, rcu);
kfree(node);
}
/**
* sel_netnode_hashfn_ipv4 - IPv4 hashing function for the node table
* @addr: IPv4 address
*
* Description:
* This is the IPv4 hashing function for the node interface table, it returns
* the bucket number for the given IP address.
*
*/
static u32 sel_netnode_hashfn_ipv4(__be32 addr)
{
/* at some point we should determine if the mismatch in byte order
* affects the hash function dramatically */
return (addr & (SEL_NETNODE_HASH_SIZE - 1));
}
/**
* sel_netnode_hashfn_ipv6 - IPv6 hashing function for the node table
* @addr: IPv6 address
*
* Description:
* This is the IPv6 hashing function for the node interface table, it returns
* the bucket number for the given IP address.
*
*/
static u32 sel_netnode_hashfn_ipv6(const struct in6_addr *addr)
{
/* just hash the least significant 32 bits to keep things fast (they
* are the most likely to be different anyway), we can revisit this
* later if needed */
return (addr->s6_addr32[3] & (SEL_NETNODE_HASH_SIZE - 1));
}
/**
* sel_netnode_find - Search for a node record
* @addr: IP address
* @family: address family
*
* Description:
* Search the network node table and return the record matching @addr. If an
* entry can not be found in the table return NULL.
*
*/
static struct sel_netnode *sel_netnode_find(const void *addr, u16 family)
{
u32 idx;
struct sel_netnode *node;
switch (family) {
case PF_INET:
idx = sel_netnode_hashfn_ipv4(*(__be32 *)addr);
break;
case PF_INET6:
idx = sel_netnode_hashfn_ipv6(addr);
break;
default:
BUG();
}
list_for_each_entry_rcu(node, &sel_netnode_hash[idx], list)
if (node->nsec.family == family)
switch (family) {
case PF_INET:
if (node->nsec.addr.ipv4 == *(__be32 *)addr)
return node;
break;
case PF_INET6:
if (ipv6_addr_equal(&node->nsec.addr.ipv6,
addr))
return node;
break;
}
return NULL;
}
/**
* sel_netnode_insert - Insert a new node into the table
* @node: the new node record
*
* Description:
* Add a new node record to the network address hash table. Returns zero on
* success, negative values on failure.
*
*/
static int sel_netnode_insert(struct sel_netnode *node)
{
u32 idx;
u32 count = 0;
struct sel_netnode *iter;
switch (node->nsec.family) {
case PF_INET:
idx = sel_netnode_hashfn_ipv4(node->nsec.addr.ipv4);
break;
case PF_INET6:
idx = sel_netnode_hashfn_ipv6(&node->nsec.addr.ipv6);
break;
default:
BUG();
}
list_add_rcu(&node->list, &sel_netnode_hash[idx]);
/* we need to impose a limit on the growth of the hash table so check
* this bucket to make sure it is within the specified bounds */
list_for_each_entry(iter, &sel_netnode_hash[idx], list)
if (++count > SEL_NETNODE_HASH_BKT_LIMIT) {
list_del_rcu(&iter->list);
call_rcu(&iter->rcu, sel_netnode_free);
break;
}
return 0;
}
/**
* sel_netnode_destroy - Remove a node record from the table
* @node: the existing node record
*
* Description:
* Remove an existing node record from the network address table.
*
*/
static void sel_netnode_destroy(struct sel_netnode *node)
{
list_del_rcu(&node->list);
call_rcu(&node->rcu, sel_netnode_free);
}
/**
* sel_netnode_sid_slow - Lookup the SID of a network address using the policy
* @addr: the IP address
* @family: the address family
* @sid: node SID
*
* Description:
* This function determines the SID of a network address by quering the
* security policy. The result is added to the network address table to
* speedup future queries. Returns zero on success, negative values on
* failure.
*
*/
static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid)
{
int ret;
struct sel_netnode *node;
struct sel_netnode *new = NULL;
spin_lock_bh(&sel_netnode_lock);
node = sel_netnode_find(addr, family);
if (node != NULL) {
*sid = node->nsec.sid;
ret = 0;
goto out;
}
new = kzalloc(sizeof(*new), GFP_ATOMIC);
if (new == NULL) {
ret = -ENOMEM;
goto out;
}
switch (family) {
case PF_INET:
ret = security_node_sid(PF_INET,
addr, sizeof(struct in_addr),
&new->nsec.sid);
new->nsec.addr.ipv4 = *(__be32 *)addr;
break;
case PF_INET6:
ret = security_node_sid(PF_INET6,
addr, sizeof(struct in6_addr),
&new->nsec.sid);
ipv6_addr_copy(&new->nsec.addr.ipv6, addr);
break;
default:
BUG();
}
if (ret != 0)
goto out;
new->nsec.family = family;
ret = sel_netnode_insert(new);
if (ret != 0)
goto out;
*sid = new->nsec.sid;
out:
spin_unlock_bh(&sel_netnode_lock);
if (ret != 0)
kfree(new);
return ret;
}
/**
* sel_netnode_sid - Lookup the SID of a network address
* @addr: the IP address
* @family: the address family
* @sid: node SID
*
* Description:
* This function determines the SID of a network address using the fastest
* method possible. First the address table is queried, but if an entry
* can't be found then the policy is queried and the result is added to the
* table to speedup future queries. Returns zero on success, negative values
* on failure.
*
*/
int sel_netnode_sid(void *addr, u16 family, u32 *sid)
{
struct sel_netnode *node;
rcu_read_lock();
node = sel_netnode_find(addr, family);
if (node != NULL) {
*sid = node->nsec.sid;
rcu_read_unlock();
return 0;
}
rcu_read_unlock();
return sel_netnode_sid_slow(addr, family, sid);
}
/**
* sel_netnode_flush - Flush the entire network address table
*
* Description:
* Remove all entries from the network address table.
*
*/
static void sel_netnode_flush(void)
{
u32 idx;
struct sel_netnode *node;
spin_lock_bh(&sel_netnode_lock);
for (idx = 0; idx < SEL_NETNODE_HASH_SIZE; idx++)
list_for_each_entry(node, &sel_netnode_hash[idx], list)
sel_netnode_destroy(node);
spin_unlock_bh(&sel_netnode_lock);
}
static int sel_netnode_avc_callback(u32 event, u32 ssid, u32 tsid,
u16 class, u32 perms, u32 *retained)
{
if (event == AVC_CALLBACK_RESET) {
sel_netnode_flush();
synchronize_net();
}
return 0;
}
static __init int sel_netnode_init(void)
{
int iter;
int ret;
if (!selinux_enabled)
return 0;
for (iter = 0; iter < SEL_NETNODE_HASH_SIZE; iter++)
INIT_LIST_HEAD(&sel_netnode_hash[iter]);
ret = avc_add_callback(sel_netnode_avc_callback, AVC_CALLBACK_RESET,
SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
if (ret != 0)
panic("avc_add_callback() failed, error %d\n", ret);
return ret;
}
__initcall(sel_netnode_init);